Flexible internal heater



Nov. 15, 1966 L. P. HYNES FLEXIBLE INTERNAL HEATER 2 Sheets-Sheet 1Filed April 6, 1964 INVENTOR Z 6 7/1 55 4A1: TORNEYS P. HYNES 3,286,078

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United States Patent 3,286,078 FLEXIBLE INTERNAL HEATER Lee P. Hynes,Haddonfield, N.J., assignor to Hynes Electric Heating Company,Kenilworth, N.J., a corporation of New Jersey Filed Apr. 6, 1964, Ser.No. 357,397

- 2 Claims. (Cl. 219-306) The present invention relates to electricheaters for fluids and more particularly to flexible internal heatersfor fluid conduits in the form of flexible hose, bent rigid pipe, orother irregular shapes.

A purpose of the invention is to provide an electric 'heater which canbe used internally within a fluid conduit in the form of a flexible hoseor bent rigid tubing.

A further purpose of the invention is to provide a flexible electricheater which can be readily inserted within or withdrawn from a flexiblehose or bent rigid tubing.

A further purpose of the invention is to provide a flexib'le electricheater wherein the heater elements can be readily inserted and withdrawnfrom an enclosure in the form of a flexible metal tubing.

A further purpose is to provide an electric heater which has a highflexibility and great resistance to fatigue failure from repeatedbending.

A further purpose of the invention is to provide insulators whichsupport and space resistors from a flexible metal tubing while allowingflexibility of the resistors and insulator to accommodate the contourand bending of the hose.

A further purpose of the invention is to provide a flexible electricheater which is positioned inside a hose.

A further purpose of the invention is to provide a flexible heater forthe inside of a hose wherein the resistor elements can be readilyremoved and inserted into a flexible metal tubing.

A further purpose'is to provide an electric heater wherein heaterelements can be chosen to achieve performance characteristics over awide range of requirements, including wattage, voltage, and temperature.

A further purpose is to provide an electric heater which can be readilyassembled to any length specification.

A further purpose is' to use commercial flexible metal tubing in aflexible electric heater.

A further purpose is to provide a heater for vaporizing fluids.

A' further purpose is to provide a flexible sealed heater for normallyinaccessible locations and irregular shaped areas where heat isrequired.

A further purpose of the invention is to utilize repetitive insulatorelements and continuous lengths of resistors and flexible metal tubingin a flexible internal heater to satisfy a wide variety of requirements.

A further purpose is to provide a flexible heater having a standardflexible casing which can be readily assembled with a selected resistorto provide any desired heat output with available voltage.

A further purpose is to provide ease of assembly and disassembly whenreplacing elements.

A further purpose is to use rigid insulator supports in the form ofmatching semi-cylindrical elements bound together with an enclosingstrap, binder or band.

A further purpose is to provide recesses in the insulator into which theband or binder can be depressed from its normal curvature to providetension on the band.

A further purpose is to recess a band or binder into an insulator tokeep the band or binder below the surface of the insulator and toprevent interference with the flexible metal tubing.

A further purpose is to use rigid insulator segments in a flexibleheater which are in pivotal relationship to one another along theresistors.

3,286,078 Patented Nov. 15, 1966 Further purposes appear in thespecification and in the claims.

In the drawings I have chosen to illustrate a few only of the numerousembodiments in which my invention may appear, selecting the forms shownfrom the standpoints of convenience in illustration, satisfactoryoperation and clear demonstration of the principles involved.

FIGURE 1 is a fragmentary view of the hose and heater of the invention.

FIGURE 2 is an enlarged sectional view of the upstream end of the heaterand housing.

FIGURE 3 is a perspective view of one half of a fulcrum insulator usedin the invention.

FIGURE 4 is a perspective view of a pivot insulator used in theinvention.

FIGURE 5 is a fragmentary view partly sectional of the downstream end ofthe heater.

I FIGURE 6 is a section taken on the line 66 of FIG- URE 5.

FIGURE 7 is a section taken on the line 7-7 of FIG- URE 6.

FIGURE 8 is an enlarged axial section taken on the line 8-8 of FIGURE 7.

FIGURE 9 is a section taken on the line 9-9 of FIG- URE 7.

FIGURE 10 is an enlarged section taken on the line 16-10 of FIGURE 7.

Describing in illustration but not in limitation and referring to thedrawings:

The present invention is concerned with heating fluids in conduits inthe form of flexible hose, bent rigid tubing, or other irregular shapes,where the conduit is generally of metal.

The invention will be explained, for purposes of clarity, in use with aflexible hose, but it should be understood that the same principlesapply to the other uses, including those stated above. Flexible hosesare extensively used for loading and unloading fluids between transportvehicles and fixed pipe lines or reservoirs. Transport vehicles includeships, railroad tank cars, barges, and tank trucks.

These flexible hoses are normally exposed to the weather during use.When the weather is cold, the fluids in the hose often tend to solidifyor freeze, so that fiow is greatly restricted or stopped. For instance,materials such as tallows, greases, waxes, pitch, asphalt, heavychemicals, and the like solidify readily at the cooler temperatures andflow is not possible.

In the prior art, efforts have been made to heat these hoses in order tosoften or condition the fluids for more ready flow. These effortsincluded steam or flame torches applied to the outside of the hose toget flow started. This has been unsatisfactory because of lack ofcontrol, creation of a fire hazard, and substantial loss of heat to theatmosphere. In other instances, tracer lines have been used along theoutside of the hoses but these have been unsatisfactory because of thedifliculty of installation, maintenance, and protection from externaldamage.

In most prior art efforts, the heat has not been applied Where mostnecessary, namely, on the inside of the hose in the fluid beingconveyed. Prior art internal heaters have included those shown in myUnited States Patent 2,750,487 and 2,963,539, where a small degree offlexibility is obtained by using a longitudinal supporting strap alongone side of the insulators. However, such heaters wer not suflicientlyflexible for use in flexible hoses or irregularly bent rigid pipes whichare commonly used in conveying fluids, particularly from or to transportvehicles.

In the heater of the present invention, a flexible metal tubingcontaining insulated flexible resistors extends within the flexible hoseconduit and heats the fluid within the hose conduit. The upstream end ofthe heater is anchored at a T-connection, and suitable electrical leadsare attached to the heater at that point. The downstream end of theflexible heater is allowed to float freely within the hose. The flexiblemetal tubing of the heater is entirely closed so that complete isolationof the live resistors of the heater from the fluid is obtained. In thisway, the action of the resistors is not interfered with and the fluid isnot contaminated. The assembly of insulated resistors can be readilyinserted and withdrawn from the flexible metal tubing while the heateris in position wthin a hose, or, in the alternative, the entire flexibleheater including the flexible metal tubing and insulated resistors canbe withdrawn from the hose. The resistors are flexibly insulated andsupported within the flexible metal tubing by repetitive, alternate,pivoted, rigid, insulators.

As shown in the drawings and referring to FIGURE 1, fluid flows from anysuitable source through the conduit 2-0 in the direction shown by thearrow 22. This fluid can be of any type including heavy oils, greases,waxes, pitch and many other materials. A T-connection 23 having sideoutlets 24 and 25 is connected at 26 by means of a suitable flange 27 toflange 21 of the supply conduit 20. A conventional flexible hose 28,generally metallic, having a flange 30 is bolted by means of bolts 31 tothe flange 24 of T26. The flexible hose 28 can be, for instance, of atype having an inner transversely corrugated structure 31 and an outerbraided metal cover 32. The hose can extend for any suitable length andhas at its downstream end a flange 33 or other connector, or, in otherinstances, a plain end which can be used for pouringor discharging intoa suitable vessel. The material which enters at 22 flows out of theflexible hoseat 34 in the direction shown by the arrow. The conduit 20and hose 28 are of conventional prior art construction.

The heater 29 of the invention is inserted through T26 into hose 28through side outlet 25. The heater 29 of the invention consists of aterminal portion 35 and a heater portion 36. Terminal portion 35 as seenin FIG- URES 1 and 2 includes a flange 38 which is held to flange 25 bybolts 40. A suitable gasket 41 provides a fluid seal between flanges 25and 38. The flange 38 has a central annular opening 42 which has securedand sealed thereto at 43 a flexible metal tubing 44. The flexible metaltubing 44 can be of any suitable type, for instance, one havingalternate corrugations of extensions 45 and depressions 46 in a wellknown bellows fashion. Metal tubing of this type has excellentflexibility and resistance to kinking. The tubing 44 is secured inopening 42 at 43 as by welding or other means to provide a completelyfluid tight connection to the flange 38. At the downstream end towarddischarge 34, flexible tubing 44 has a sealed end cap 47 as best seen inFIGURE which is welded to the flexible metal tubing 44 at 48. By meansof the seal at 43 and the seal at 48, the interior of flexible tubing 44is completely isolated from the fluid flow which occurs inthe hose 28from the inlet 22 to the outlet 34. The flexible metal tubing 44 can bemade of any desired length.

Considering now the terminal portion 35, a flange 51 is secured toflange 38 by means of cap screws 52. Flange 51 has an annular opening at53. Flange 51 has integral therewith terminal block 54 mountinginsulated electrical terminals 55 and 56.

Extending .within flexible metal tubing 44 is a heating element 57. Theheating element 57 consists of resistors 58 and 60 which are shown asbeing helically wound but which may be of any suitable type. Theresistors 58 and 60 may be for instance, of a round cross section wireor of a flat ribbon. The resistors are connected at terminal portion 35to terminals 55 and 56. At the other end of the heater element 57 asbest seen in FIG- URE 6, the resistors 58 and 60 are suitably spliced bymeans of a metal element 61 either welded or crimped to the end of theresistors. Alternatively, the resistors 58 and could be integral andmerely bent rather than spliced.

Suitable electric leads 62 and 63 pass through terminal box 64 which issuitably integral with flange 38. Leads 62 and 63 pass through packing65 and follower 66 to make a waterproof connection. A cap 67 is screwedonto terminal box 64 to provide a weatherproof enclosure for the entireelectrical assembly and prevent moisture or other foreign matter fromentering the terminal box 64 as well as the interior of the flexiblemetal tubing 44.

The resistors 58 and 60 are supported and spaced within flexible metaltubing 44 by fulcrum insulators 68 and pivot insulators 70. Consideringfirst the fulcrum insulators 68, each insulator consists of twoidentical semi-cylindrical portions -71 and 72. Since the halves 71 and72 are identical, only one half 71 as best seen in FIGURE 3 will bedescribed in detail. Portion 71 has a curved surface 69 and opposingflat ends 73. Additionally, resistor half 71 has a flat, longitudinallyextending plane surface 73' which extends in spaced parallelrelationship with a fl-at surface 73 on an opposed half 72. Suitablesemi circular channels or grooves 74 and 75 as best seen in FIGURES 3and 6 extend longitudinally of the insulator halves 71 and 72 and are ofa size which properly grips and supports the resistors 58 and 60. Eachof the portions 71 and 72 of the fulcrum insulators 68 has a transversegroove 76 which is adapted to receive the connector 61 at the end of theresistors, which serves to connect the resistors together at the endopposite the terminals 55 and 56. It will be evident that although allof the fulcrum insulators will carry such transverse grooves, only theendmost fulcrum insulator will be utilized for the purpose of crossconnecting the resistors. This is clearly shown in FIGURE '6 where theend of the insulator away from the resistor as at 77 acts as a suitablebarrier for insulating the end of the resistor at 61 away from theflexible tubing 44 at the end cap 47.

Matching fulcrum insulator halves 71 and 72 are held in spaced grippingrelationship about the resistors 58 and 60, as best seen in FIGURE 8, bya band or strap 78 which lies in a recessed groove 80 which extendsannularly around the longitudinal midsection of the insulator halves 71and 7 2.

The groove 80 has recesses or slots 81 below groove 80 at a positionmidway on the circumference, the slot being best seen in perspective inFIGURE 3 and in section in FIGURE 8. The slot receives in one instance asplice 82 suitably in the form of bent interlocked ends of the band 78depressed into the' slot. In a slot 81 opposite to the splice 82, theband is depressed as at 83 into the slot to achieve a tensioning of theband during or after the splice 82 is completed. Both the splice 82 andthe depression 83 may be performed by any suitable tool, such as clamps,vices or opposed jaws. It should be understood that splice or joint 82is merely illustrative and that band 78 could be spliced by anysuit-able means such as spot welding or other fastenings.

In applying the band 78 and also in the subsequent splicing andtensioning by means of depression 83, the insulators 71 and 72 grip theresistors 58 and 60 securely in their longitudinally extending grooves74 and 75 in a resilient but firm manner, whereby relative longitudinalmovement between the fulcrum insulators 68 and the resistors 58 and 60is prevented.

Pivot insulators 70, as best seen in FIGURE 4, are

alternately spaced between the fulcrum insulators 68, as shown inFIGURES 5 to 7. The pivot insulator 70 consists of a cylindrical portion85 and abutment portions 86 suitably integral with portion 85. Theabutment portion 86 is tapered at 87 with an end abutment at 88. Theportion 85 has extending therethrough 1ongitudinally extending opposedslots 89 which receive the resistors 58 and 68 as best seen in FIGURES5, 6 and 9. The resistors 58 and 60 resiliently abut against the innerportions of the slots 89 so that the pivot insulator 7t) is firmly heldpositioned between the fulcrum insulators 68 but is not fixedlyconnected thereto. The resistors 58 and 60 serve to resiliently holdinsulators 68 and 70 in abutting relationship at faces 73 and 88respectively while allowing the insulators 68 and 70 to pivot in auniversal direction with respect to one another at these faces toachieve flexibility as flexible tubing 44 bends to conform to thecontour of flexible conduit hose 28.

The abutment portion 86 of pivot insulator 70 additionally serves as aninsulating barrier between resistors 58 and 60 at all times, as shownparticularly in FIGURES 6 and 9, whether the heater 29 is flexed or in astraight position.

A temperature sensing device 90 with suitable leads 91 may be insertedthrough, or attached to, the surface of the flow conduit at any desiredlocation to sense the fluid temperature for control purposes.

In operation, the connection between the inlet conduit 20 and theflexible hose 28 is provided by a T- connection 23 having flanges oneach end as described above. The heater portion 36 of flexible heater 29is inserted into the side opening of the T-connection 23 at 25 andpushed into the interior of the flexible hose 28. The heater portion 36is pushed into the hose until the flange 38 of the terminal portion 35abuts against flange 25 and the flanges are bolted together by bolts 40.The heater portion 36 will have already inserted within flexible metaltubing 44, the assembly of the resistors 58 and 60 and the insulators 68and 70 as taught in the description above. The resistors 58 and 60 willbe connected to terminals 55 and 56 as by screw connections and suitableelectric current will be applied to the resistors through conductors 62and 63. The end cap 67 is then threaded onto the terminal box 64 so thatthe electrical connections as well as the resistors and insulators arefully protected against moisture and other elements.

In assembling the resistors and insulators prior to insertion intoflexible tubing 44, the fulcrum insulators 68 are applied to theresistors by assembling the halves 71 and 72 in opposed relationship asshown, for instance, in FIGURE 8 and the band 78 applied in place aroundeach pair of insulators in the groove 80. The band is then spliced at 82and the band 78, at a diametrically opposed position is then depressedat 83 to apply the proper tension to the band. A pivot insulator 70 isplaced adjacent the fulcrum insulator 68 into a position describedabove. Another fulcrum insulator 68 is brought into position in abuttingrelationship as shown in FIGURES 5 to 7. The second fulcrum insulator isthen held in position around the resistors by applying the band 78 in amanner already described. Alternate fulcrum and pivot insulators areapplied along the entire length of the resistors. Fulcrum insulators areused at both ends of the assembly. The pivot insulator 70 is thenconfined between a pair of fulcrum insulators 68 and the resitors 58 and60 so that it is kept securely in position while allowing freedom ofmovement of the resistors, so that the pivot insulators can toggle atboth ends against the fulcrum insulators. This provides de- :siredflexibility throughout the length of the resistors to conform to thecontour of the flexible metal tubing 44 which in turn conforms to thechanging contour of the flexible hose 28.

It will be seen that by removing bolts 40, the entire heater 29 can beremoved from its installation in flexible hose 28 by merely withdrawingthe entire terminal portion 35 which in turn withdraws the flexiblemetal tubing 44 which is permanently attached thereto. In the event thatit is further desired to withdraw the heater element 57 from within theflexible metal tubing 44, it is merely necessary to unscrew cap 67,remove the connections of leads 62 and 63 from terminals 55 and 56, andremove cap screws 52 from flange 38. Terminal block 54, with integralflange 51, and heater element 57 may then be withdrawn from withinflexible tubing 44. Suitable replacements can be made of, for instance,the resistor elements where different requirements have to be met by theheater. In the event that it is desired. to change the heat output ofthe heater element, or if the resistors or other parts should fail, theycan be readily replaced by disassembling and reassembling with newresistors or replacement parts without disturbing any fluid connections.

In view of my invention and disclosure, variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the structure shown, and I, therefore, claimall such insofar as they fall within the reasonable spirit and scope ofmy claims.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. In a flexible fluid heater adapted to extend within a fluid enclosurethrough an opening in the fluid enclosure, a terminal portion, aflexible, bendable, metallic tube secured to said terminal portion atone end and closed at the other end whereby fluid. is prevented fromentering into the metallic tube, flexible, bendable, substantiallylongitudinally non-stretchable and longitudinally non-compressible,self-supporting, parallel resistors extending longitudinally within thetube and extending into the terminal portion, rigid sectional fulcruminsulators spaced. longitudinally along the resistors, each of the saidinsulators comprising radial sections with resistor receiving portionswithin the sections, and tensioning means on each of the insulators forsecurely holding each of the insulators in secure gripping relationshipto the resistors; each of said insulators having an outer radial surfacegenerally conforming in shape to the inner surface of the metal tube,said insulator outer surface and said tube inner surface being inbearing relationship, wherein the resistors are free to bend atpositions longitudinally between fulcrum insulators and. are securelygripped and held within the fulcrum insulator-s.

2. A heater of claim 1, in combination with pivot insulators extendinglongitudinally between the fulcrum in sulators, said pivot insulatorshaving longitudinal grooves adapted to receive the resistors inlongitudinal sliding relationship thereto.

References Cited by the Examiner UNITED STATES PATENTS 1,699,323 1/1929Apfel 219306 1,829,785 11/1931 Christian 219-335 2,058,769 10/1936 Brown2l9-33l X 2,064,248 12/1936 Doyon 219331 2,888,546 5/1959 Kinney 219528X 2,963,539 12/1960 Hynes 174138.8 3,016,441 1/1962 Hackman et al.174-138.8 X 3,017,688 1/1962 Cummings et al. 338214 X FOREIGN PATENTS398,589 9/1933 Great Britain. 32,387 3/ 1934 Netherlands.

RICHARD M. WOOD, Primary Examiner.

C. L. ALBRITTON, Assistant Examiner.

1. IN A FLEXIBLE FLUID HEATER ADAPTED TO EXTEND WITHIN A FLUID ENCLOSURETHROUGH AN OPENING IN THE FLUID ENCLOSURE, A TERMINAL PORTION, AFLEXIBLE, BENDABLE, METALLIC TUBE SECURED TO SAID TERMINAL PORTION ATONE END AND CLOSED AT THE OTHER END WHEREBY FLUID IS PREVENTED FROMENTERING INTO THE METALLIC TUBE, FLEXIBLE, BENDABLE, SUBSTANTIALLYLONGITUDINALLY NON-STRETCHABLE AND LONGITUDINALLY NON-COMPRESSIBLE,SELF-SUPPORTING, PARALLEL RESISTORS EXTENDING LONGITUDINALLY WITHIN THETUBE AND EXTENDING INTO THE TERMINAL PORTION, RIGID SECTIONAL FULCRUMINSULATORS SPACED LONGITUDINALLY ALONG THE RESISTORS, EACH OF THE SAIDINSULATORS COMPRISING RADIAL SECTIONS WITH RESISTOR RECEIVING PORTIONSWITHIN THE SECTIONS, AND TENSIONING MEANS ON EACH OF THE INSULATORS FORSECURELY HOLDING EACH OF THE INSULATORS IN SECURE GRIPPING RELATIONSHIPTO THE RESISTORS; EACH OF SAID INSULATORS HAVING AN OUTER RADIAL SURFACEGENERALLY CONFORMING IN SHAPE TO THE INNER SURFACE OF THE METAL TUBE,SAID INTULATOR OUTER SURFACE AND SAID TUBE INNER SURFACE BEING INBEARING RELATIONSHIP, WHEREIN THE RESISTORS ARE FREE TO BEND ATPOSITIONS LONGITUDINALLY BETWEEN FULCRUM INSULATORS AND ARE SECURELYGRIPPED AND HELD WITHIN THE FULCRUM INSULATORS.